Effective seal forming device



June 25, 1968 c 3 ET AL 3,389,917

EFFECTIVE SEAL FORMING DEVICE 2 Sheets-Sheet 1 Filed June 22, 1966 0 lI. v {a 3 x56 g Cw 0; ix; plum Mm .Jm 1. 6 a w M b n 3 L w/ v 4 ATTORNEYJune 25, 1968 MCGILL ET AL 3,389,917

EFFECTIVE SEAL FORMING DEVICE Filed June 22, 1966 2 Sheets-Sheet 2flan/0rd 1. Ma 6/// /Vam6v' 6. J/wf/f, a}:

INVENTORS BY/JM /f? ATTORNEY United States Patent "ice 3,389,917EFFECTIVE SEAL FORMING DEVICE Howard L. McGill and Homer G. Smith, Jr.,Houston,

Tex., assignors to Schlumberger. Technology Corporation, Houston, Tex.,a corporation of Texas Filed June 22, 1966, Ser. No. 559,465 Claims.(Cl. 277-63) ABSTRACT OF THE DISCLOSURE An anti-extrusion system for awell tool packing element comprising an annular member having slotsextending from alternate end surfaces of said member to points adjacentalternate opposite end surfaces to divide said member into a pluralityof segments having interconnected end portions, the interconnected endportions adjacent said packing element engaging said packing element toprevent extrusion of said packing element past said segments underpressure.

This invention relates generally to well tools, and more particularly tomeans for providing an effective seal in a well conduit. 3

For packing-off or plugging a well conduit, a well tool usually includesa pliant, elastomer packing element carried around a mandrel. Whenpositioned within the well conduit, the packing element of the well toolfunctions to seal off the annular space between the mandrel and thesurrounding wall of the well conduit. The packing element is normallysupported against any substantial longitudinal movement relative to themandrel by an annular shoulder or abutment extending outwardly of themandrel.

In order that the well tool be freely shiftable within the well conduitprior to the effecting of a seal, a clearance space is provided betweenthe outer surfaces of the well tool and the wall of the well conduit.Under the influence of compression forces, high pressures andtemperatures, or any combination of these factors, the elastomer packingelement may attempt to flow or extrude through the clearance space,resulting in deformation of the packing element and possible failure ofthe seal. Furthermore, if the well tool is to be subsequently retrievedfrom the well conduit, that portion of the packing element which hasbeen forced into annular clearance space can cause the well tool tobecome anchored within the well conduit so that retrieval is eitherimpossible or exceedingly difficut.

Accordingly, it is an object of the present invention to provide a newand improved sealing device for a Well tool which effectively overcomesone or more of the foregoing difficulties. I

Another object of the present invention is to provide a new and improvedwell tool with a packing element arrangement to minimize cold flow orextrusion of the packing element through adjacent clearance spaces.

These and other objects are attained in a well tool by providing thewell tool with a resilient ring-like device which is selectivelyexpandable from-a normally retracted position to form a solid bridge forthe clearance space between the well tool and a well conduit. Morespecifically, the well tool body has an outwardly extending shoulderwhich supports an expandable and contractible annular member. Theannular member is formed of longitudinally extending segments with aresilient interconnection between the segments. Means movable relativeto the shoulder and the annular member are provided for expanding theannular member outwardly of the body. The annular member, when expanded,substantially closes the clearance space between the shoulder and a wellconduit.

The invention has other objects and advantages which 3,389,917 PatentedJune 25, 1968 will become more apparent from the consideration of thefollowing disclosure. Various embodiments thereof are shown in theaccompanying drawings, which, in conjunction with the following detaileddescription, will illustrate the general principles of the invention. Inthe drawings:

FIGURE 1 is an elevational view of one embodiment of the presentinvention in connection with a well tool positioned within a wellconduit;

FIGURE 2 is an enlarged partial cross-sectional view of a portion of theapparatus shown in FIGURE 1 to illustrate the principles of the presentinvention;

FIGURE 3 is a cross-sectional view of an expandable and contractibleannular member in accordance with the present invention;

FIGURE 4 is a fragmentary view which illustrates the operation of theembodiment of the invention shown in FIGURES 1-3;

FIGURE 5 is a longitudinal view, partially in section, of an alternativeembodiment of the present invention; and

FIGURE 6 is a cross-sectional view of the annular member of thealternative embodiment of FIGURE 5.

Referring now to FIG. 1, the invention is shown in connection with abridge plug 10 (only partially illustrated) which would be positionedwithin a well conduit 11 where the conduit 11 extends upwardly to theearths surface. On the bridge plug are two oppositely facing cup-typepacker elements 17, 18 attached to an operating mandrel 12 at a locationadjacent to the top of a housing 13. The packer elements are responsiveto pressure differentials from either direction across the bridge plug10 which provide forces on the operating mandrel 12 tending to move themandrel relative to the housing 13. On the bridge plug 10 is a frictionanchor 14 circumferentially spaced about the housing. Movement of themandrel relative to the anchor 14 increases the holding force of theanchor within the well conduit 11. The details of the bridge plug 10which are not essential to the present invention are fully set forth inthe patent application of James W. Kisling III, Ser. No. 482,009, nowPatent No. 3,305,022, filed July 9, 1965, for Well Packing Apparatus.From the standpoint of the present invention, cups 17 and 18 areprovided with an anti-extrusion device 26 which can be embodied on othertypes of packers and plugs aside from the specific bridge plug referredto above.

Referring now to FIG. 2, apparatus embodying the principles of thepresent invention includes a tubular mandrel or body 20 which may be,for example, the operating mandrel of the bridge plug shown in FIG. 1.Disposed around a reduced diameter portion 21 of the body 20 are theupper 17 and the lower 18 packing elements commonly known as swab cups.The inner end of each packing element is bonded or otherwise securedwithin annular recesses 22, 23 in expander members 24, 25 which areslidably received on the body. Disposed around the body 20 intermediatethe packing elements is an expandable and contractible annular member 26having an inwardly extending flange 27 received between an outwardlyextending flange 28 of the reduced body portion 21 and a nut member 30threadedly secured to the reduced body portion.

The annular member 26 has upper and lower inner inclined surfaces 31, 32which diverge outwardly of the body 20, the surfaces complementarilyengage inwardly converging surfaces 33, 34 on the upper and lowerexpander members 24, 25, respectively, so that longitudinal movement ofeither of the expander members is translated to outward movement of theannular member 26. Suitable sealing elements 35, 36 fluidly seal betweenthe expanders 24, 25 and the reduced body portion 21. The lower end ofthe upper expander member 24 and the upper end of the lower expandermember 25 are initially spaced a distance away from the nut member 30and the outwardly extending flange 28, respectively, to permit limitedlongitudinal movement of the expander members relative to both the body20 and the annular member 26.

The annular member 26 is made radially expansible and contractible byproviding alternating series of radially cut slots 40, 41 extending fromthe ends of the annular member to points defined by radial holes 42intermediate the ends of the annular member. The slots, in effect,divide the annular member into a plurality of circumferentially spacedlongitudinally extended segments 43 which are interconnected by portions44 between each segment to form a one-piece member. The member 26 ismade of a steel or any other suitable material which has sufficientresilience to permit expansion when outward pressure is exerted on theinner inclined surfaces 33, 34 by the expander members 24, 25. When theoutward pressure is relieved by movement of an expander member away fromthe annular member, the member should possess suflicient resilience toreturn toward its original position. The annular member is held againstlongitudinal movement relative to the body 29 by the engagement of theinwardly extending flange 27 between the outwardly extending flange 28and the nut member 30 on the reduced body portion 21.

It Will be appreciated that as the annular member 26 expands outwardly,the slots 40, 41 will be widened. In order to prevent any cold fiow orextrusion of the packing elements into the slots, a plurality of platemembers are positioned around the inclined surfaces of the annularmember as shown in detail in FIG. 3. The plate members function to spanor bridge the slots to keep the slots closed at all times. Each platemember 50 has a longitudinal portion 51 which extends across adjacentslots 40, 41, a tab portion 52 which extends into a radial hole 42 inthe member 26 to fasten the plate member in place, and a radiallyoutwardly extending flange portion 53 which extends across the end facesof the annular member. Each plate member 50 is made to have sufficientcircumferential width whereby it will extend across adjacent slots 40,41 when the annular member is expanded outwardly into engagement withthe wall of the well conduit.

In operation of the apparatus illustrated in FIGS. 1-4 of the drawings,the well tool is positioned Within a well conduit. The outer surfaces ofthe packer elements 17, 18 are sized to normally engage the well conduitwalls and the outer surface of the annular member 26 is spaced from theinner wall of the conduit in its contracted condition to provide asuflicient clearance space S therebetween. When a fluid pressuredifferential is developed in a downward direction across the packerelements of the well tool, the

upper packer element 17 will shift downwardly relative to the body 20,thereby moving the upper expander 24 downwardly as shown in FIG. 4.Downward movement of the upper expander 24 is translated to outwardmovement of the annular member 26 due to the interengagement of theinclined surfaces 31, 33. The annular member 26 will expand tosubstantially fill the annular clearance space between the member andthe conduit wall and prevent the packer element 17 from cold flowing orextruding thereinto. The plate members 50 bridge the slots in theannular member adjacent the packer element so that the packer will notextrude into the slot spaces.

Conversely, an upwardly acting pressure differential across the packerelements of the well tool will activate the lower packer element 18 andexpander 25 to expand the annular member 26 into the clearance space.Movement of the expanders away from the member will allow it to contractinwardly and return to its original shape so that ample clearance isagain provided to permit shifting the well tool within the well conduit11.

From the foregoing description, it should be appreciated that the slopeof the inclined surfaces and construction of member 26 can be arrangedto obtain uniform radial expansion. It is, of course, obvious todovetail the connection between the member 26 and expanders 24, 25.

With particular reference to the alternative embodiment of the inventionas shown in FIG. 5, a tubular body 60, which may be, for example, a partof a bridge plug of the type shown in the Composite Catalog of OilfieldEquipment and Services, 19661967, page 2898, has an enlarged portion 61to provide a downwardly facing shoulder 62. A lower compression sleeve63 is slidably received on the body for longitudinal movement relativethereto. An elastomer packing device 64 isvdisposed around the body 60intermediate the shoulder 62 and the compression sleeve 63.

The upper and lower ends of the packing device 64 are bonded orotherwise secured within annular recesses 65, 66 in upper and lowerexpander members 67, 68, respectively. The expanders are slidablyreceived on the body 60 and have inwardly converging surfaces 69, 70which complementarily engage outwardly diverging inner surfaces on upperand lower annular members 71, 72. The annular members are made radiallyexpansible and contractible by providing alternating series of radiallycut slots as shown in FIG. 6, the slots extending from the ends of themembers to points defined by radial holes 73 intermediate the length ofthe member in a manner similar to the slot configuration shown in FIG.2. Similarly to the embodiment shown in FIG. 2, the slots divide thering members into a plurality of longitudinal segments 74 withconnecting portions 75 between each segment so that the members areuniformly expansible responsive to outward pressures exerted thereon bythe expanders 67, 68.

A plurality of plate members 76 are positioned around the inner inclinedsurfaces of each ring member, the plate member functioning to bridge theslot gaps or spaces to prevent cold fiow or extrusion at the packerdevice into the spaces when the annular members are expanded outwardly.Each plate member 76 has a longitudinal portion 77 and a fastening tab78 which engages in one of the holes 73. The plate members 79 whichserve to span the slot spaces extending to the ends of expandablemembers adjacent the packing device, have flange portions 80 whichextend outwardly over the member end surfaces.

Referring now to the operation of the alternative embodiment shown inFIGS. 5, 6, the well tool is positioned in-a well bore and the partoperated to cause upward movement of the compression sleeve 63 relativeto the body 60, thereby subjecting the packing device 64 to compressiveforces for expanding the packing device outwardly into sealingengagement with the wall of the well conduit 11. As this expansion takesplace, the expanders 67, 68 move relative to the annular members 71, 72and exert outward pressure thereon to expand the annular members andsubstantially close the annular clearance space S adjacent both ends ofthe packing device.

It will be appreciated that as the ring members expand, the widths ofthe slots increase. However, the plate members 76 act to bridge the slotspaces at all times so that the packer element cannot extrude thereinto.

It will now be apparent that a new and improved sealing apparatus hasbeen disclosed which provides an effective seal Within a well conduitand which prevents cold flow or extrusion of an elastomer packingelement. It will be understood that although the invention is especiallysuited for retrievable well tools, it is not confined to the specifictype of well tool described in the above-mentioned patent application,but can be used generally for preventing cold flow or extrusion of anelastomer packing element through the annular clearance space around awell tool and adjacent a packing element.

It will be understood that various changes and modifications may be madein the details of the embodiments shown without departing from theinventive concept, and it is intended that the appended claims cover allsuch changes and modifications.

We claim:

1. In a well tool, the combination comprising: a body; upper and lowerpacking devices disposed about said body and mounted for limitedlongitudinal movement relative to said body; an expansible andcontractible annular member intermediate said packing devices; meanscooperable between said body and said annular member for holding saidannular member immovable longitudinally of said body While permittingradial movement thereof outwardly of said body; and expander meansintermediate said packing devices and said annular member operable inresponse to longitudinal movement of said packing devices relative tosaid body for expanding said annular member radially outwardly of saidbody.

2. In a well tool: a body member; normally retracted anti-extrusionmeans disposed about said body member, said anti-extrusion means being aone-piece annular member having longitudinally cut slots extending fromone end surface to points adjacent the opposite end surface in analternating manner to divide said annular member into a plurality ofsegments which can be expanded outwardly, said segments having upper andlower inner inclined surfaces; upper and lower expander means cooperablewith said inclined surfaces for expanding said segments outwardly; andpacking means slidable on said body member and cooperable with one ofsaid expander means for expanding said segments outwardly to positionswhere said segments engage said packing means to prevent extrusion ofsaid packing means past said segments under pressure.

3. The well tool of claim 2 further including means between saidsegments for closing the spaces between said segments which are adjacentsaid packing means when said segments are expanded outwardly.

4. An anti-extrusion system for a well tool packing element comprising:an annular member having longitudinally cut slots extending from one endsurface to points adjacent an opposite end surface to divide saidannular member into a plurality of segments with adjacent segmentshaving interconnected end portions, said segments being expansible topositions where alternate ones of said interconnected end portionsengage said packing element to prevent extrusion of said packing elementunder pressure, said interconnected end portions also providingresilient means between said segments to enable expansion and alsocontraction of said segments relative to a well conduit wall.

5. An anti-extrusion system of claim 4 further including means betweensaid alternate ones of said interconnected end portions for bridging thespaces therebetween When said segments are expanded to prevent flow ofsaid packing into said spaces.

References Cited UNITED STATES PATENTS 2,672,199 3/1954 McKenna 166-202X 2,714,931 8/1955 Bouvier 166135 X 2,743,780 5/1956 Brown 166-202 X2,767,795 10/1956 Bush 166202 X 2,884,070 4/1959 Potts 166121 2,972,3792/1961 Brown 166-202 X 3,181,614 5/1965 Brown 166-134 X 3,298,440 1/1967Current 166135 X DAVID H. BROWN, Primary Examiner.

